Modeling preeclampsia in mice with inducible placenta-specific gene expression

具有可诱导胎盘特异性基因表达的小鼠先兆子痫模型

• 批准号: 8911995
• 负责人: Nihar R Nayak
• 金额: $ 7.9万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8911995
• 关键词: Modeling; preeclampsia; mice; inducible; placenta

Preeclampsia is a serious complication of pregnancy affecting both the mother and fetus, and causing an estimated 14% of pregnancy-related maternal deaths worldwide. Despite its large public health impact, however, its causes are still poorly understood, and there are no known treatments that effectively alleviate the risks for both mother and fetus. Based on clinical studies in the human and experimental studies in rodents, it has been suggested that the abnormal elevation of the circulating levels of soluble fms-like tyrosine kinase 1 (sFlt-1) contributes to the systemic endothelial dysfunction and clinical manifestations of the disease through its antagonism of vascular endothelial growth factor (VEGF) activity. As a result, it is believed that VEGF treatment may reverse the preeclamptic phenotype caused by high sFlt-1 levels in the maternal circulation. However, in preliminary studies, we found, surprisingly, that overexpression of VEGF in pregnant mice results in elevated blood pressure and serum levels of sFlt-1 and soluble endoglin (sEng), and histological changes in the kidneys, similar to the clinical findings of PE in humans and animal models. VEGF has been shown to stimulate sFlt-1 production in several cell types and placental explant cultures in multiple contexts. However, the roles of placental VEGF at different stages of pregnancy, the significance of regulation of its local activity by placental production of sFlt-1, and its potential role in regulating sFlt-1 production in the placenta, has never been examined, primarily due to lack of suitable animal models to test the placenta-specific effects of VEGF. We hypothesize that VEGF activity in the placenta is regulated in a placental developmental stage-specific manner during pregnancy through local production of sFlt-1, and placental VEGF levels may be a primary stimulus for increased production of sFlt-1 in this tissue. Studies in this proposal are designed, first, to develop a novel, inducible, placenta-specific gene expression system, with the ability to monitor gene expression throughout pregancy by live in vivo imaging. This technique will be based on established methods for viral delivery of genes specifically to placental tissue, effective control of consistency in gene expression levels, and a tightly controlled inducible promoter which allows expression to be rapidly switched both on and off. We will then examine the effects of different levels of placental VEGF expression at various time points during pregnancy using this inducible system. To define the physiological role of sFlt-1 during different stages of pregnancy, we will selectively knock down sFlt-1 expression in the placenta using placenta-specific expression of a short hairpin RNA (shRNA) targeted against sFlt-1. The results of these experiments will delineate, for the first time, the local interactions of VEGF and sFlt-1 in regulating VEGF activity in the placenta. Additionally, this entirely novel approach, using a newly-developed, inducible, placenta-specific gene regulation system, will greatly facilitate development of new animal models for the study of both placental disease and normal placental development, and will greatly enable the development of therapies for complications of pregnancy.

先兆子痫是一种严重的妊娠并发症，会影响母亲和胎儿，并导致 据估计，全世界 14% 的孕产妇死亡与妊娠有关。尽管其公共卫生影响巨大， 然而，其原因仍然知之甚少，并且没有已知的治疗方法可以有效缓解 对母亲和胎儿都有风险。基于人类临床研究和啮齿动物实验研究， 有人认为可溶性 fms 样酪氨酸激酶 1 的循环水平异常升高 (sFlt-1) 通过以下方式导致全身内皮功能障碍和疾病的临床表现 其拮抗血管内皮生长因子（VEGF）活性。因此，人们认为 VEGF 治疗可能会逆转母体循环中高 sFlt-1 水平引起的先兆子痫表型。 然而，在初步研究中，我们令人惊讶地发现，怀孕小鼠中 VEGF 的过度表达会导致 血压升高、血清 sFlt-1 和可溶性内皮糖蛋白 (sEng) 水平升高，以及组织学变化 肾脏，类似于人类和动物模型中 PE 的临床结果。 VEGF 已被证明可以 在多种情况下刺激多种细胞类型和胎盘外植体培养物中 sFlt-1 的产生。然而， 胎盘VEGF在妊娠不同阶段的作用及调节其局部活性的意义 胎盘产生 sFlt-1 的作用及其在调节胎盘中 sFlt-1 产生中的潜在作用，从未 进行了检查，主要是由于缺乏合适的动物模型来测试 VEGF 的胎盘特异性作用。 我们假设胎盘中的 VEGF 活性受到胎盘发育阶段特异性的调节 妊娠期间通过局部产生 sFlt-1 的方式，胎盘 VEGF 水平可能是主要的 刺激该组织中 sFlt-1 的产生增加。本提案中的研究首先旨在开发 一种新型、可诱导、胎盘特异性基因表达系统，能够监测基因表达 整个怀孕期间通过活体成像。该技术将基于已建立的病毒检测方法 将基因特异性递送至胎盘组织，有效控制基因表达水平的一致性，以及 严格控制的诱导型启动子，允许快速打开和关闭表达。我们将 然后检查不同时间点胎盘 VEGF 表达水平的影响 使用这种诱导系统怀孕。明确 sFlt-1 在不同阶段的生理作用 怀孕后，我们将使用胎盘特异性表达选择性地敲低胎盘中 sFlt-1 的表达 靶向 sFlt-1 的短发夹 RNA (shRNA)。这些实验的结果将描述，对于 首次发现 VEGF 和 sFlt-1 局部相互作用调节胎盘中 VEGF 活性。另外，这 全新的方法，使用新开发的、可诱导的、胎盘特异性基因调控系统，将 极大地促进了用于胎盘疾病和正常研究的新动物模型的开发 胎盘发育，并将极大地促进妊娠并发症疗法的开发。

项目成果

Endometrial VEGF induces placental sFLT1 and leads to pregnancy complications.

子宫内膜 VEGF 诱导胎盘 sFLT1 并导致妊娠并发症。

• 发表时间: 2014-11
• 作者: Fan, Xiujun;Rai, Anshita;Kambham, Neeraja;Sung, Joyce F;Singh, Nirbhai;Petitt, Matthew;Dhal, Sabita;Agrawal, Rani;Sutton, Richard E;Druzin, Maurice L;Gambhir, Sanjiv S;Ambati, Balamurali K;Cross, James C;Nayak, Nihar R
• 通讯作者: Nayak, Nihar R